1. Field of the Invention
The present invention relates to an apparatus and method for mitigating inter-cell interference in a wireless communication system. More particularly, the present invention relates to an apparatus and method for mitigating inter-cell interference in a wireless communication system, which uses a femto Base Station (BS).
2. Description of the Related Art
In cellular wireless communication systems, Mobile Stations (MSs) positioned at cell edges fall under interference from adjacent cells. In recent years, attention is being paid to an inter-cell interference mitigation technique that makes use of limited coordination. For example, the inter-cell interference mitigation technique includes a Collision Avoidance-Beam Forming (CA-BF) technique and a Precoding Matrix Index (PMI) coordination technique.
Regarding the CA-BF technique, a master scheduler schedules BSs inducing inter-cell interference such that the inter-cell interference is minimized. That is, the master scheduler performs scheduling such that a sum capacity is maximized using PMI information provided from the BSs through a backhaul.
Regarding the PMI coordination technique, BSs determine a precode or matrix for beamforming using PMI information exchanged with other BSs through the backhaul.
A wireless communication system provides a femto-cell service for providing a high-speed data service while addressing a service problem of a propagation shadow area. Here, the femto cell denotes a service area of a compact BS, which has access to a mobile communication core network through a commercial broadband network.
With respect to providing the femto-cell service, dozens of femto cells can exist within a macro cell. In this case, the macro cell and femto cells need a lot of backhaul capacity to exchange information with each other. In addition, there is a problem in that, as the number of cells adjacent to an MS increases, an amount of information that the MS feeds back to a serving station increases and adjacent cell information for the serving station to consider in order to mitigate inter-cell interference also increases, thereby increasing a complexity for mitigating the inter-cell interference.